Bovine herpesvirus-1 (BHV-1) is known to cause several diseases worldwide. It is a double-stranded DNA virus consisting of 33 structural proteins out of which 13 are associated with the envelope. Based on genomic analysis and viral peptide patterns, BHV-1 virus can be divided into several subtypes like BHV-1.1, BHV-1.2, and BHV-1.3. However, all subtypes are antigenically similar. The symptoms of the related diseases are mainly non-life-threatening but have a rather wide host range that limits animal trade. The different modes of transmission as unique feature of this virus and the tendency to cause infection in the early age with latency development in trigeminal and sacral ganglion cause huge economic losses around the world. The virus also affects endangered bovine species like mithun (Bos frontalis) and yak (Poephagus grunniens). The disease can be diagnosed by using conventional procedures (like cell culture, immune-histopathology, and enzymelinked immunosorbent assay (ELISA)) as well as highly sensitive modern techniques (like nested PCR and southern hybridization) with the virus neutralization test regarded as gold standard. With the currently available diagnostic tests it is not possible to identify animals which have a latent BHV-1 infection. Different types of modern and conventional vaccines are available for immunoprophylaxis. Inactivated vaccines are not as efficacious as modified live virus (MLV) vaccines. Marker vaccines allow the distinction between vaccinated and naturally infected animals. In this review the present status of BHV-1 around the world will be addressed besides the current knowledge with regard to its biology, epidemiology, diagnosis, and prophylaxis.
Trace elements, though required in minute quantities (less than 100 mg/kg dry matter), are essential for maintaining health and immunity. They are involved in growth, production and reproduction. Trace elements act as cofactors of enzymes which are important to the immunity of animal. Superoxide dismutase , glutathione reductase, glutathione peroxidase, thioredoxin reductase, ceruloplasmin and catalase are important enzymes that have trace elements as cofactors. These enzymes act as antioxidants and prevent oxidative stress by neutralizing oxidants produced under different stresses. Besides, trace elements contribute to general health of animal thereby enhancing disease resistance. Trace elements are important for proper functioning of a number of enzymes and proteins which are involved in many physiological, biochemical and metabolic processes that contribute to growth and production. Overall, trace elements improve immune competence and productive performance.
BackgroundIn the view of endemic avian influenza H9N2 infection in poultry, its zoonotic potential and emergence of antiviral resistance, two herbal plants, Ocimum sanctum and Acacia arabica, which are easily available throughout various geographical locations in India were taken up to study their antiviral activity against H9N2 virus. We evaluated antiviral efficacy of three different extracts each from leaves of O. sanctum (crude extract, terpenoid and polyphenol) and A. arabica (crude extract, flavonoid and polyphenol) against H9N2 virus using in ovo model.MethodsThe antiviral efficacy of different leaves extracts was systematically studied in three experimental protocols viz. virucidal (dose-dependent), therapeutic (time-dependent) and prophylactic (dose-dependent) activity employing in ovo model. The maximum non-toxic concentration of each herbal extracts of O. sanctum and A. arabica in the specific pathogen free embryonated chicken eggs was estimated and their antiviral efficacy was determined in terms of reduction in viral titres, measured by Haemagglutination (HA) and real time quantitative reverse transcription polymerase chain reaction (RT-qPCR) assays.ResultsAll the extracts of O. sanctum (crude extract, terpenoid and polyphenol) and A. arabica (crude extract, flavonoid and polyphenol) showed significant virucidal activity, however, crude extractocimum and terpenoidocimum showed highly significant to significant (p < 0.001–0.01) decrease in virus genome copy numbers with lowest dose tested. Similarly, therapeutic effect was observed in all three extracts of O. sanctum in comparison to the virus control, nevertheless, crude extractocimum and terpenoidocimum maintained this effect for longer period of time (up to 72 h post-incubation). None of the leaves extracts of A. arabica had therapeutic effect at 24 and 48 h post-incubation, however, only the crude extractacacia and polyphenolacacia showed delayed therapeutic effect (72 h post-inoculation). Prophylactic potential was observed in polyphenolacacia with highly significant antiviral activity compared to virus control (p < 0.001).ConclusionsThe crude extract and terpenoid isolated from the leaves of O. sanctum and polyphenol from A. arabica has shown promising antiviral properties against H9N2 virus. Future investigations are necessary to formulate combinations of these compounds for the broader antiviral activity against H9N2 viruses and evaluate them in chickens.
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